Compressor utilizing spaces between cylinder bores

ABSTRACT

A compressor C has a construction comprising a cylinder block  1  in which cylinder bores  1   a  are formed, a front housing  2  and a rear housing  4  which are arranged at the front and at the rear, respectively, of the cylinder block  1 . Pistons  20  which are accommodated in each cylinder bore  1   a  so as to be able to reciprocate, are connected to the cam plate  12 , which connects to a drive shaft  6  so as to be able to integrally rotate, so as to operate, and the pistons  20  compress refrigerant gas according to the rotation of the drive shaft  6 . A suction muffler  40 , a discharge muffler  41  and a control valve  31  are provided between the cylinder bores  1   a  in the cylinder block  1 . Further, a unit  60  which comprises a discharge check valve and an oil separator is disposed in the suction muffler  40.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a refrigerant compressor and, moreparticularly, to a refrigerant compressor of which the housing size canbe reduced and the configuration of the housing can be designed morefreely.

2. Description of the Related Art

A housing in a piston type compressor generally comprises a cylinderblock, a front housing connected to the front thereof, and a rearhousing connected to the rear thereof. A drive shaft which receivesdriving power from an external driving source, a cam plate connected tothe drive shaft so as to be operated thereby, and pistons connected tothe cam plate so as to be operated thereby are arranged in an areaextending from the front housing to the cylinder block. In addition,cylinder bores, in which each piston is accommodated so as to be able toreciprocate, are arranged in the cylinder block. Also, a suction chamberinto which refrigerant gas sucked into the cylinder bores is introducedand a discharge chamber into which refrigerant gas discharged from thecylinder bores is introduced are arranged in the rear housing.

Moreover, the compressors may further comprise mufflers which damppulsations transmitted via refrigerant gas to an evaporator and acondenser from the inside of the compressor, check valves which preventrefrigerant gas from flowing reversely, an oil separator which separatesa mist of lubrication oil, mixed with refrigerant gas, from therefrigerant gas, a displacement control valve which varies the dischargedisplacement of the refrigerant gas by changing the stroke of thepistons by pressure control, and so on, as additional componentsrequired to increase its function.

As the inside of the cylinder block is occupied by the cylinder boreswhen the additional components (mufflers, check valves, an oil separatorand a displacement control valve) are arranged in the compressor, theyare arranged in the front housing or the rear housing.

There is, however, a difficulty in design to provide a space forarranging the additional components because members, such as an armwhich attaches the compressor to other members (for example, a vehicleside engine) are located in the front housing and the rear housing. Asuction hole and a discharge hole which are communication passages withthe outside of the compressor and most of the additional components areconcentratedly arranged specially in the rear housing, because thesuction chamber and the discharge chamber are closely located around therear housing. These reasons make the rear housing and, as a result, thecompressor, bulky.

SUMMARY OF THE INVENTION

The objective of the present invention is to provide a compressor inwhich the size of a housing thereof can be reduced and also theconfiguration of the housing can be designed more freely.

In order to solve the above problems, the first aspect of the presentinvention is a compressor; wherein a crank chamber is formed in ahousing, also a drive shaft is supported so as to be able to rotate,cylinder bores are formed in a cylinder block, each piston isaccommodated in each cylinder bore so as to be able to reciprocatetherein, a cam plate is connected to the drive shaft so as to operate,the pistons are connected to the cam plate so as to operate, and thepistons reciprocate according to the rotation of the drive shaft so thatrefrigerant gas is sucked and discharged; the cylinder block, which ispositioned between the front housing and the rear housing, comprises atleast two of a suction space through which refrigerant gas sucked intothe cylinder bores passes, a discharge space through which refrigerantgas discharged from the cylinder bores passes, a suction side checkvalve which is positioned upstream the suction space preventsrefrigerant gas introduced into the suction space from reversely flowingupstream the suction space, a discharge side check valve which ispositioned downstream the discharge space prevents refrigerant gasdischarged from the discharged space to downstream side from reverselyflowing into the discharge space, an oil separator which separates amist of lubrication oil, mixed with refrigerant gas, from therefrigerant gas, and a control valve which varies the pressure in thecrank chamber which accommodates the cam plate, between the cylinderbores in the cylinder block.

In this invention, by arranging at least two of the suction space, thedischarge space, each check valve, the oil separator, and the controlvalve between the cylinder bores in the cylinder block, protrudingvolumes of each of the above-mentioned parts (the suction space, thedischarge space, each check valve, the oil separator, and the controlvalve), outside the housing of the compressor, can be reduced. As theresult, the size of the housing can be reduced and also theconfiguration of the housing (specially for front housing and rearhousing) can be designed more freely.

The second aspect of the present invention is that, in the first aspectof the present invention, “N” (N is an integral number which is not lessthan 2) sets of cylinder bores are provided in the cylinder block, andnot less than N of the suction space, the discharge space, the suctionside check valve, the discharge side check valve, the oil separator, andthe control valve are provided between the cylinder bores in thecylinder block.

In this invention, by comprising N sets of cylinder bores in thecylinder block, regions between the same cylinder bores are formed innumber “IN”. By effectively utilizing the N sets of regions, those, notless than N, of the suction space, the discharge space, the suction sidecheck valve, the discharge side check valve, the oil separator, and thecontrol valve are disposed in the regions so that the size of thehousing can be more preferably reduced and also the configuration of thehousing can be designed more freely.

The third aspect of the present invention is that, in the second aspectof the present invention, at least one of the suction space, thedischarge space, the suction side check valve, the discharge side checkvalve, the oil separator, and the control valve are provided betweeneach cylinder bore in the cylinder block.

In this invention, all of the regions between the cylinder bores areutilized for disposing at least one of the suction space, the dischargespace, the suction side check valve, the discharge side check valve, theoil separator, and the control valve therein. That is to say, all of theregions between the cylinder bores are utilized for such disposition.This allows that the size of the housing can be more preferably reducedand also the configuration of the housing can be designed more freely.

The fourth aspect of the present invention is that, in any one of thefirst aspect to third aspect of the present invention, at least one ofthe suction space or the discharge space are provided between thecylinder bores in the cylinder block.

In this invention, the suction space and the discharge space, whichrequire relatively large space, are disposed in the cylinder block, sothat the size of the compressor can be effectively reduced and also theconfiguration of the housing can be designed more freely.

The fifth aspect of the present invention is that, in any one of thesecond aspect to fourth aspect of the present invention, the dischargespace is provided between the cylinder bores in the cylinder block andat least one of the discharge side check valve or the oil separator aredisposed in the discharge space.

In this invention, the discharge space is utilized to dispose at leastone of the discharge side check valve or the oil separator therein sothat the regions between the cylinder bores are utilized moreeffectively. Thus the size of the housing can be more preferably reducedand also the configuration of the housing can be designed more freely.

The sixth aspect of the present invention is that, in any one of thefirst aspect to fifth aspect of the present invention, the pressuredifference, through the piston, between the pressure in the crankchamber and the pressure in the cylinder bores is varied by the controlvalve, and then the inclination angle of the cam plate is changedaccording to the pressure difference, so that the compressor is avariable displacement type which controls the discharge displacementthereof.

In this invention, the compressor is constructed as a variabledisplacement type and a control valve having a relatively large volumeis added to the optional components which are disposed between cylinderbores in the cylinder block so that the size of the housing of thecompressor of variable displacement type can be more effectively reducedand also the configuration of the housing can be designed more freely.

The seventh aspect of the present invention is that, in the sixth aspectof the present invention, cylinder bores, which number not less thanthree, are provided in the cylinder block and the suction space, thedischarge space and the control valve are provided between the cylinderbores in the cylinder block.

In this invention, the suction space, the discharge space and thecontrol valve which require a relatively large space are disposedbetween the cylinder bores 1 a in the cylinder block, so that the sizeof the compressor can be effectively reduced and also the configurationof the housing can be designed more freely.

The present invention may be more fully understood from the descriptionof the preferred embodiments of the invention set forth below, togetherwith the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

In the drawings:

FIG. 1 is a cross-sectional view that illustrates the outline of oneembodiment of a compressor.

FIG. 2 is a sectional view that illustrates the arrangement of eachmuffler of the compressor.

FIG. 3 is a cross-sectional view that illustrates the outline of a checkvalve and an oil separator of the compressor.

FIG. 4 is an enlarged plan view in viewing the valve portion from anupper direction.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

An embodiment of the present invention is described below with referenceto FIG. 1 and FIG. 2.

As shown in FIG. 1, a compressor C comprises a cylinder block 1, a fronthousing 2 coupled to the front end of the cylinder block 1, and a rearhousing 4 coupled to the rear end of the cylinder block 1 via a valveforming body 3. Thus the cylinder block 1, the front housing 2, thevalve forming body 3, and the rear housing 4, are coupled and fixed toeach other by plural (6 pieces in this embodiment) through-bolts 10(only one is shown in FIG. 1), and constitute a housing of thecompressor C. In the region surrounded by the cylinder block 1 and thefront housing 2, a crank chamber 5 is defined. In the crank chamber 5, adrive shaft 6 is supported by a pair of radial bearings 8A and 8B, onein front and one in rear, so that a reciprocating motion is enabled. Aspring 7 and a rear thrust bearing 9B are disposed in a housing recessformed in the center of the cylinder block 1. On the other hand, a lugplate 11 is fixed on the drive shaft 6 in the crank chamber 5 so that areciprocating motion is integrally enabled and a front thrust bearing 9Ais disposed between the lug plate 11 and the internal wall surface ofthe front housing 2. The drive shaft 6 and the lug plate 11 bothintegrally coupled are positioned in a thrust direction (in the axialdirection of the drive shaft 6) by a front thrust bearing 9A and a rearthrust bearing 9B which are biased forward by a spring 7.

The front end of the drive shaft 6 is connected to a vehicle engine E,which functions as an external driving source, via a power transmissionmechanism PT. The power transmission mechanism PT may be a clutchmechanism (for example, an electromagnetic clutch) which can select thetransmission and the isolation of power by an external electric controlor may be a clutch-less mechanism of a permanent connection type (forexample, a combination of a belt and a pulley) which does not comprisesuch a clutch mechanism. In this embodiment a power transmissionmechanism of a clutch-less type is employed.

As shown in FIG. 1, a swash plate 12 as a cam plate is housed in a crankchamber 5. A through hole is penetrated through the center portion ofthe swash plate 12 and the drive shaft 6 is positioned in the throughhole. The swash plate 12 is coupled to the lug plate 11 and the driveshaft 6 via the hinge mechanism 13, as a coupling guide mechanism, so asto be operated. The hinge mechanism 13 comprises two supporting arms 14(only one is shown) protruding from the rear surface of the lug plate 11and two guide pins 15 (only one is shown) protruding from the frontsurface of the swash plate 12. The swash plate 12 can synchronouslyrotate with the lug plate 11 and the drive shaft 6 by cooperation withthe support arms 14 and the guide pins 15 and by contact with driveshaft 6 in the center through hole of the swash plate 12 and can alsotilt, with respect to the drive shaft 6, accompanied by the slidingmovement in an axial direction of the drive shaft 6. In addition, inthis case the inclination angle (inclination) of the swash plate 12 isdefined as the angle formed between the virtual plane perpendicular tothe drive shaft 6 and the swash plate 12.

Plural (three in this embodiment) cylinder bores 1 a (only one is shownin FIG. 1) are formed, in a cylinder block 1, surrounding the driveshaft 6 and the rear end of each cylinder bore 1 a is closed by thevalve forming body 3. A single-headed piston 20 is housed in eachcylinder bore 1 a so that a reciprocating motion is enabled and acompression chamber which varies its volume according to thereciprocating motion of the piston 20 is defined in the each cylinderbore 1 a. The front end of the each piston 20 is connected to the outercircumferential portion of the swash plate 12 via a pair of shoes 19 andeach piston 20 is coupled to the swash plate 12 via the shoes 19 so asto be operated. This enables the rotating motion of the swash plate 12to be converted to a reciprocating linear motion of the pistons 20 witha stroke corresponding to the inclination angle thereof when the swashplate 12 synchronously rotates with the drive shaft 6.

Further, between the valve forming body 3 and the rear housing 4, adischarge chamber 21 which constitutes a discharge space locating at thecenter area and a suction chamber 22 which constitutes a suction spacesurrounding the discharge chamber 21 are defined. The valve forming body3 consists of a suction valve forming plate 3A, a port forming plate 3B,a discharge valve forming plate 3C and a retainer forming plate 3D in astacked manner thereof. The respective forming plates are stacked andsecured by a pin 3E. A suction port 23 and a suction valve 24 whichopens and closes the same port 23, and a discharge port 25 and adischarge valve 26 which opens and closes the same port 25 are formed inthe valve forming body 3 in a manner they are located corresponding toeach cylinder bore 1 a. The suction chamber 22 communicates with eachcylinder bore 1 a via the suction port 23 and each cylinder bore 1 acommunicates with the discharge chamber 21 via the discharge port 25.

The discharge chamber 21 connects to the crank chamber 5 through asupply passage 30. A control valve 31 is provided on the way in thesupply passage 30. In addition, a pressure detecting passage 32 whichintroduces a suction pressure Ps into the control valve 31 is formedbetween the suction chamber 22 and the control valve 31. Further, thesuction chamber 22 connects to the crank chamber 5 through a bleedpassage 33.

The control valve 31 has the same construction as that of thedisplacement control valve shown in FIG. 1 in the publication ofJapanese unexamined patent application (Kokai) no. 10-141221. That is,the position of the valve portion 38 is designed to be varied, accordingto the balance of biasing forces created by a solenoid portion 34, abellows 35, a forcedly opening spring 36 and an auxiliary spring 37, sothat the opening of the supply passage 30 is regulated. The solenoidportion 34 is actuated by a current output by an electric drive circuit,not shown, based on the signal from a control computer, not shown. Thebellows 35 expands and retracts based on the value of a suction pressurePs transmitted from the suction chamber 22 through the pressuredetecting passage 32.

The balance between the flow rate of high pressure gas to the crankchamber 5 through the supply passage 30 and the flow rate of gas fromthe crank chamber 5 through the bleed passage 33 is controlled byadjusting the opening of the control valve 31 and then the crankpressure Pc is determined thereby. The pressure difference between thecrank pressure Pc and the internal pressure in the cylinder bore 1 a,via the piston 20, is varied according to the change of the crankpressure Pc and the inclination angle of the swash plate 12 is changed,to regulate the stroke of the piston 20, that is, the dischargedisplacement.

As shown in FIG. 1 and FIG. 2, the control valve 31 is arranged in aportion of areas between each cylinder bore 1 a, along through from thecylinder block 1 to the rear housing 4, so that the longitudinaldirection of the control valve 31 is in parallel to the axial directionof the drive shaft 6. As shown in FIG. 2, a suction muffler 40 whichconstitutes a suction space and a discharge muffler 41 which constitutesa discharge space are also formed, respectively, in the residual twoportions of areas between each cylinder bore 1 a in cylinder block 1.Each muffler 40 and 41 is formed with a cross section of anapproximately triangle shape so as to come near each cylinder bore 1 aso that they lie through inside the cylinder block 1 from front to rearand the spaces between each cylinder bore 1 a can be utilizedeffectively as far as possible. For illustration, however, in FIG. 1,the cylinder bores 1 a are shown to have a smaller diameter than that ofFIG. 2.

The rear side (the rear housing 4 side) of the suction muffler 40communicates with the suction chamber 22 and a suction hole 40A whichcommunicates an external refrigerant circuit 50, described below, withthe suction muffler 40 is provided in the front side (the front housing2 side) of the suction muffler 40.

The rear side of the discharge muffler 41 communicates through thedischarge chamber 21 and a discharge hole 41A which communicates theexternal refrigerant circuit 50, described below, with the dischargemuffler 41 is provided in the front side of the discharge muffler 41.

The suction hole 40A connects to the discharge hole 41A through theexternal refrigerant circuit 50. The external refrigerant circuit 50,for example, comprises a condenser 51, a temperature type expansionvalve 52 and an evaporator 53. The opening of the temperature typeexpansion valve 52 is feedback-controlled based on the temperaturedetected by a thermo-sensing coupler 54 provided at an outlet side or adownstream side of the evaporator 53 and based on the evaporatingpressure (the outlet pressure of the evaporator). The temperature typeexpansion valve 52 supplies refrigerant liquid to the evaporator 53corresponding to heat load and regulates the flow rate of refrigerant inthe external refrigerant circuit 50. A communication tube 55 forrefrigerant gas which connects the outlet of the evaporator 53 to thesuction hole 40A of the compressor C is provided in a downstream regionof the external refrigerant circuit 50. A communication tube 56 forrefrigerant which connects the discharge hole 41A of the compressor C tothe inlet of the condenser 51 is provided in an upstream region of theexternal refrigerant circuit 50.

As shown in FIG. 2, a unit 60 is attached on the discharge muffler 41.The unit 60 is coupled to, and fixed on, the inner circumferential wallsurface of the cylinder block 1 so as to cover the discharge hole 41A.

As shown in FIG. 3, the unit 60 comprises an approximately cylindricalcase 62 with a bottom and a check valve 61 housed in the case 62. Thecheck valve 61 comprises an approximately cylindrical casing 63, with abottom, of which an end surface at an opening side is coupled to, andfixed on, the circumferential wall surface of the cylinder block 1. Avalve chamber 63A is formed in the casing 63 with the end surface atopening side of the casing 63 covered by the circumferential wallsurface of the cylinder block 1. A valve inlet 63B, as an inlet forrefrigerant, is provided in a bottom of the casing 63. In addition, onthe contrary, the discharge hole 41A is provided to function as anoutlet for the refrigerant. A valve portion 65 is housed in the valvechamber 63A so as to be able to reciprocate between the valve inlet 63Band the discharge hole 41A. The valve portion 65 is constructed to bebiased against the valve inlet 63B side by a valve closing spring 66.

The valve portion 65 has an approximately cylindrical shape with abottom and a portion of a bottom side thereof is formed in a taperedshape with gradually smaller diameter in the direction toward topthereof. When the valve portion 65 is biased against the valve inlet 63Bside, a part of this tapered portion enters into the valve inlet 63B toclose the valve inlet 63B. The outer circumferential surface of thevalve portion 65 has plural (four in this embodiment) grooves 65Adirecting in the axial direction of the valve portion 65 (refer to FIG.4 which is a view wherein the valve portion 65 is viewed from theopening side thereof). A cutout 65B is formed on the end surface of thevalve portion 65 at the opening side in the groove 65A and the outerside of the valve portion 65 communicates with the inner side thereof.When the valve portion 65 is moved to the circumferential wall surfaceside of the cylinder block 1 against the biasing force of the valveclosing spring 66, the opening side of the valve portion 65 comes intocontact with the circumferential wall surface so as to restrict furthermovement. Then, though the discharge hole 41A is designed to be coveredby the opening side of the valve portion 65, the valve inlet 63Bcommunicates with the discharge hole 41A via the grooves 65A and thecutout 65B.

The opening and the closing of the valve inlet 63B is operated by thebalance between biasing force of refrigerant pressure at an upstreamside of the check valve 61 against the valve portion 65, the biasingforce of refrigerant pressure at a downstream side of the check valve 61against the valve portion 65, and the biasing force of the valve closingspring 66, so that the refrigerant is prevented from flowing reversely.When the biasing force of the upstream side pressure exceeds the totalforce of the biasing force of the downstream side pressure and thebiasing force of the valve closing spring 66, the check valve 61 permitsthe refrigerant to flow. On the contrary, when the biasing force of theupstream side pressure becomes smaller than the total force of thebiasing force of the downstream side pressure and the biasing force ofthe valve closing spring 66, the check valve 61 does not permit therefrigerant to flow. That is, the check valve 61 can prevent therefrigerant from flowing reversely from the downstream side (theexternal refrigerant circuit 50 side) to the upstream side (thedischarge chamber 21 side). In this case, the check valve 61 functionsas a discharge side check valve which prevents the refrigerant,discharged from the discharge muffler 41 to the downstream outside ofthe discharge muffler 41, from flowing reversely to the dischargemuffler 41.

In the state in which the check valve 61 is housed in the case 62, theopening side of the case 62 is covered by the circumferential wallsurface of the cylinder block 1, so that a separating chamber 62A isdefined. An introducing port 62B which introduces refrigerant in thedischarge muffler 41 into the separating chamber 62A is provided in thecase 62. The introducing port 62B is provided along the circumferentialdirection of the case 62 so that refrigerant introduced into theseparating chamber 62A rotates in the separating chamber 62A. As acasing 63 of the check valve 61 is located in the separating chamber62A, actually the refrigerant introduced from the introducing port 62Bto the separating chamber 62A rotates in a clearance between the innercircumferential surface of the case 62 and the outer circumferentialsurface of the casing 63. This rotating motion centrifugally separateslubrication oil, mixed with the refrigerant, so that the lubrication oiladheres to the inner circumferential surface of the case 62.

Further, a tapered inclined recess 62D is provided on the bottom of thecase 62 so that the lubrication oil which adheres on the innercircumferential surface of the case 62 and drops down is collected inthe deepest portion of the inclined recess 62D. A drain passage 62Ewhich discharges the lubrication oil out of the unit 60 is provided inthe deepest portion of the inclined recess 62D. The lubrication oildrained out of the unit 60 through the drain passage 62E is introducedinto the upstream side of the control valve 31 in the supply passage 30through an oil supply passage, not shown, so as to be supplied to thecrank chamber 5. However, an oil separator which separates the mist oflubrication oil, mixed with refrigerant, is constituted by the case 62,the casing 63 and the circumferential wall surface of the cylinder block1.

Next, the functions of the compressor constituted as described above aredescribed. Driving power is supplied from an vehicle engine E to thedrive shaft 6 via a power transmission mechanism PT and then the swashplate 12 rotates together with the driving shaft 6. Each piston 20reciprocates according to the rotation of the swash plate 12 in a strokecorresponding to the inclination angle of the swash plate 12 and thesuction, the compression and the discharge of refrigerant is repeated,in turn, in each cylinder bore 1 a.

When the cooling load is high, the control computer sends a commandsignal to the electric driving circuit so that the value of the currentsupplied to the solenoid portion 34 increases. The variation of thecurrent value from the electric driving circuit based on the signalallows the solenoid portion 34 to increase the biasing force so that thevalve portion 38 further decreases the opening of the supply passage 30.As the result, the bellows 35 decreases the opening of the supplypassage 30 by actuating the valve portion 38. Thus the flow rate of highpressure refrigerant gas supplied from the discharge chamber 21 to thecrank chamber 5 via the supply passage 30 decreases, the pressure of thecrank chamber 5 is lowered, the inclination angle of the swash plate 12increases, and the discharge displacement of the compressor C increases.When the opening of the supply passage 30 is fully closed, the pressureof the crank chamber 5 decreases in large amount, the inclination angleof the swash plate 12 increases to the maximum, and the dischargedisplacement of the compressor C increases to the maximum.

On the contrary, when the cooling load is low, the solenoid portion 34decreases the biasing force so that the valve portion 38 furtherincreases the opening of the supply passage 30. As the result, thebellows 35 increases the opening of the supply passage 30 by actuatingthe valve portion 38. Thus the pressure of the crank chamber 5 israised, the inclination angle of the swash plate 12 decreases and thedischarge displacement of the compressor C decreases. When the openingof the supply passage 30 is fully open, the pressure of the crankchamber 5 is raised in large amount, the inclination angle of the swashplate 12 decreases to the minimum and the discharge displacement of thecompressor C decreases to the minimum.

The refrigerant, discharged to the discharge chamber 21 after beingcompressed in the cylinder bores 1 a, is introduced into the dischargemuffler 41 and reaches the external refrigerant circuit 50 via the unit60 and the discharge hole 41A. Then the pulsation of the refrigerant,created when the refrigerant is discharged from the cylinder bores 1 a,is damped while it is transmitted to the discharge hole 41A side via thedischarge chamber 21 and the discharge muffler 41. Thus the pulsationtransmitted to the condenser 51 is lowered. Then the refrigerant, whichreaches the suction hole 40A from the external refrigerant circuit 50,is introduced into the suction chamber 22 after passing through thesuction muffler 40, and is sucked into the cylinder bores 1 a so as tobe compressed. The pulsation of the refrigerant, created when therefrigerant is sucked into the cylinder bores 1 a, is damped while it istransmitted to the suction hole 40A side via the suction chamber 22 andthe suction muffler 40. Thus the pulsation transmitted to the evaporator53 is lowered.

The refrigerant (a mist of lubrication oil is mixed in this refrigerant)introduced into the separating chamber 62A via the introducing port 62Bof the unit 60 rotates in the clearance between the innercircumferential surface of the case 62 and the outer circumferentialsurface of the casing 63 of the check valve 61. After the lubricationoil is centrifugally separated during rotation thereof and is collectedinto the inclined recess 62D, it is introduced into the crank chamber 5via the drain passage 62E, the oil supply passage, the supply passage 30and the control valve 31. The lubrication oil introduced into the crankchamber 5 lubricates components of the mechanism (such as bearings, ahinge mechanism, etc.) in the crank chamber 5.

The refrigerant separated from the lubrication oil is prone to flow intothe valve chamber 63A via the valve inlet 63B. Then the refrigerantpushes the valve portion 65 up, passes through the clearance, formedbetween the bottom portion of the valve portion 65 and the valve inlet63B, so as to flow into the valve chamber 63A, passes through thegrooves 65A and reaches the valve hole 41A. When the valve portion 65comes into contact with the circumferential wall surface of the cylinderblock 1 by being pushed up by the refrigerant, the refrigerant, afterpassing through the grooves 65A, reaches the discharge hole 41A throughthe clearance formed by the circumferential wall surface and the cutout65B. The refrigerant which reaches the outside of the valve chamber 63Athrough the discharge hole 41A flows into the external refrigerantcircuit 50 through the communication tube 66 and provides the heatexchanging effect.

This embodiment can provide the following effect.

(1)

Because the suction muffler 40 and the discharge muffler 41 are arrangedbetween the cylinder bores 1 a in the cylinder block 1, it is notrequired that both mufflers 40 and 41 are arranged to protrude outside(specially in the radial direction of the drive shaft 6) the housing ofthe compressor C or are provided in other configuration separated fromthe housing thereof. That is, the size of the compressor C can bereduced. As both mufflers 40 and 41 have such structures that require arelatively large volume, the effect due to the prevention of a sizeincrease thereof is remarkable. It can provide a cost reduction comparedto the case in which both mufflers 40 and 41 are formed in otherconfigurations separated from the housing of the compressor C.

(2)

Because the control valve 31 is arranged between the cylinder bores 1 ain the cylinder block 1, the protrusion of the control valve 31 to therear housing 4 side can be reduced. That is, the volume of the rearhousing 4 can be reduced, which contributes to a reduction in the sizeof the compressor C.

(3)

The control valve 31 is arranged between the cylinder bores 1 a in thecylinder block 1 and the protrusion of the control valve 31 to the rearhousing 4 side can be reduced, so that the configuration of the rearhousing 4 can be designed more freely. Therefore, the configuration ofthe rear housing 4 can have higher priority in fabrication processthereof and a cost reduction is possible. In addition, such members asan arm, etc. which is used to attach the compressor C to other members(for example, the vehicle engine E at a vehicle side, etc.) are easy toinstall on the rear housing 4.

(4)

The utilization of the spaces between the cylinder bores 1 a in thecylinder block 1 for arranging the control valve 31 permits the size ofthe control valve 31 to be increased without increasing the size of thecompressor C.

(5)

The control valve 31 is arranged between the cylinder bores 1 a in thecylinder block 1, so that the control valve 31 can be located near thecrank chamber 5. That is, the supply passage 30 can be shortened and theresponse of the control of the discharge displacement can be improved.

(6)

By utilizing the spaces between all cylinder bores 1 a in the cylinderblock 1, the suction muffler 40, the discharge muffler 41 and thecontrol valve 31 are provided. Thus the spaces between the cylinderbores 1 a in the cylinder block 1 are utilized without waste, so thatreduction in the size of the compressor C is further facilitated.

(7)

The check valves 61 and the oil separator are provided in the dischargemuffler 41. This enables the compressor C to comprise the preventionfunction of the check valves 61 for the reverse flow of refrigerant (forthe refrigerant discharged to the downstream side of the dischargemuffler 41 to flow reverse to the discharge muffler 41), the preventionfunction of the oil separator for discharging lubrication oil to theexternal refrigerant circuit 50 side and the lubricating function of theoil separator for the crank chamber 5, and can reduce the size of thecompressor C.

Embodiments are not restricted to those mentioned above, and thefollowing embodiments are possible.

Between the cylinder bores 1 a in the cylinder block 1, instead ofproviding the suction muffler 40 and the discharge muffler 41, thesuction side check valve, which prevents the refrigerant from reverselyflowing from the suction chamber 22 to the communication tube 55, andthe discharge side check valve (the check valve 61), which prevents therefrigerant from reversely flowing from the communication tube 56 to thedischarge chamber 21, may be provided.

Between the cylinder bores 1 a in the cylinder block 1, instead ofproviding the suction muffler 40 and the discharge muffler 41, an oilseparator, which separates a mist of lubrication oil, mixed withrefrigerant, from the refrigerant, may be provided.

At least one of the suction side check valve or the oil separator may beprovided in the suction muffler 40 provided between the cylinder bores 1a in the cylinder block 1.

At least one of the discharge side check valve (the check valve 61) orthe oil separator may be provided in the discharge muffler 41.Otherwise, none of them may be provided therein.

The suction muffler 40 or the discharge muffler 41 may be providedbetween the cylinder bores 1 a in the cylinder block 1. None of themufflers, however, may be provided between the cylinder bores 1 a in thecylinder block 1.

The control valve 31 may be provided between the cylinder bores 1 a inthe cylinder block 1.

The longitudinal direction of the control valve 31 may not be providedin parallel to the axial direction of the drive shaft 6.

The control valve 31 may be a type that does not have a pressure sensingmember such as the bellows 35. That is, it may have such a constructionthat regulates the opening of the supply passage 30 by moving a valveportion, directly connected to a solenoid, by external control of acurrent.

The control valve 31 may not be the external control type which iscontrolled by an external device such as the control computer, theelectric drive circuit, etc. and may be the internal control type whichprovides a completely independent control.

Instead of the construction in which a cam plate (the swash plate 12)integrally rotates with the drive shaft 6, the compressor C may be suchtype as a oscillation (wobble) type compressor in which a cam plate issupported by a drive shaft and oscillates so as to enable rotationrelatively with respect to the drive shaft.

The compressor C may be a fixed displacement type in which the stroke ofthe pistons 20 can not be changed.

The number of cylinder bores 1 a need not be three, but may be, forexample, two or not less than four cylinders.

Both mufflers 40 and 41 may protrude outside the cylinder block 1 (theradial direction of the drive shaft 6) as far as they are arrangedbetween the cylinder bores 1 a.

Some of the suction muffler 40, the discharge muffler 41, the suctionside check valve, the discharge side check valve (the check valve 61),the oil separator and the control valve 31 may be provided in thecylinder block 1 and their numbers are less than the numbers of thespaces between the cylinder bores 1 a.

The plural same components of the suction mufflers 40, the dischargemufflers 41, the suction side check valves, the discharge side checkvalves (the check valves 61), the oil separators and the control valves31 may be provided between the cylinder bores 1 a in the cylinder block1.

In order to provide at least two of the suction muffler 40, thedischarge muffler 41, the suction side check valve, the discharge sidecheck valve (the check valve 61), the oil separator and the controlvalve 31 in the cylinder block 1, it is not necessary to utilize all theregions between the cylinder bores 1 a.

As described in detail above, according to the present invention, in acompressor, the size of a housing thereof can be reduced and also theconfiguration of the housing can be designed freely.

While the invention has been described by reference to specificembodiments chosen for the purposes of illustration, it should beapparent that numerous modifications could be made thereto by thoseskilled in the art without departing from the basic concept and scope ofthe invention.

What is claimed is:
 1. A compressor; wherein a crank chamber is formedinside a housing and a drive shaft is supported so as to be able torotate, cylinder bores are formed in a cylinder block, each piston isaccommodated in each cylinder bore so as to be able to reciprocatetherein, a cam plate is connected to the drive shaft so as to operate,the pistons are connected to the cam plate so as to operate, and thepistons reciprocate according to the rotation of the drive shaft so thatrefrigerant gas is sucked and discharged; and wherein the cylinderblock, which is positioned between the front housing and the rearhousing, comprises at least two of a suction space through whichrefrigerant gas sucked into the cylinder bores passes, a discharge spacethrough which refrigerant gas discharged from the cylinder bores passes,a suction side check valve which is positioned upstream the suctionspace and also prevents refrigerant gas introduced into the suctionspace from reversely flowing upstream the suction space, a dischargeside check valve which is positioned downstream the discharge space andalso prevents refrigerant gas discharged from the discharged space tothe downstream side thereof from reversely flowing into the dischargespace, an oil separator which separates a mist of lubrication oil, mixedwith refrigerant gas, from the refrigerant gas, and a control valvewhich varies the pressure in the crank chamber which accommodates thecam plate, between the cylinder bores in the cylinder block.
 2. Acompressor, as set forth in claim 1, wherein “N” (N is an integralnumber which is not less than 2) sets of the cylinder bores are providedin the cylinder block, and not less than N, of the suction space, thedischarge space, the suction side check valve, the discharge side checkvalve, the oil separator, and the control valve are provided between thecylinder bores in the cylinder block.
 3. A compressor, as set forth inclaim 2, wherein at least one of the suction space, the discharge space,the suction side check valve, the discharge side check valve, the oilseparator, and the control valve are provided between each cylinder borein the cylinder block, respectively.
 4. A compressor, as set forth inclaim 1, wherein at least one of either the suction space or thedischarge space are provided between the cylinder bores in the cylinderblock.
 5. A compressor, as set forth in claim 2, wherein the dischargespace is provided between the cylinder bores in the cylinder block andat least one of either the discharge side check valve or the oilseparator are disposed in the discharge space.
 6. A compressor, as setforth in claim 1, wherein the pressure difference, through the piston,between the pressure in the crank chamber and the pressure in thecylinder bores is varied by the control valve, and then the inclinationangle of the cam plate is changed according to the pressure difference,so that the compressor is allowed to be a variable displacement typewhich controls the discharge displacement thereof.
 7. A compressor, asset forth in claim 6, wherein not less than three cylinder bores areprovided in the cylinder block and the suction space, the dischargespace and the control valve are provided between the cylinder bores inthe cylinder block.
 8. A compressor, as set forth in claim 6; whereinthe control valve includes a solenoid which operates due to an electricpower supply from an external control device; and wherein the controlvalve is located between the cylinder bores in the cylinder block.
 9. Acompressor, as set forth in claim 6, wherein the longitudinal directionof the control valve is approximately parallel to the axial direction ofthe drive shaft.